Nucleostemin: a multiplex regulator of cell-cycle progression.
Nucleostemin (NS) is a protein concentrated in the nucleolus of most stem cells and also in many tumor cells, which has been implicated in cell-cycle progression owing to its ability to modulate p53. Depletion of NS causes G(1) cell-cycle arrest, but its overexpression does so as well. Recently, this paradox has been clarified. NS overexpression causes a sequestration of murine double minute 2 (MDM2), preventing the destruction of p53. A recent study has demonstrated that loss of NS promotes the interaction of L5 and L11 ribosomal proteins with MDM2 and, thus, also prevents p53 degradation. This new finding expands our understanding of the multiple modes of NS action and reinforces the concept that the nucleolus has key roles in cell-cycle progression.
Ma
Hanhui
H
Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01609, USA. hanhui.ma@umassmed.edu
Pederson
Thoru
T
D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle; D019204:GTP-Binding Proteins; D006801:Humans; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D051736:Proto-Oncogene Proteins c-mdm2 / Q000378:metabolism; D012269:Ribosomal Proteins / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*
D002352:Carrier Proteins; C469949:GNL3 protein, human; D009687:Nuclear Proteins; D012269:Ribosomal Proteins; D016159:Tumor Suppressor Protein p53; D051736:Proto-Oncogene Proteins c-mdm2; D019204:GTP-Binding Proteins